Magnetite-arginine nanoparticles as a multifunctional biomedical tool. - In: Nanomaterials, ISSN 2079-4991, Bd. 10 (2020), 10, 2014, insges. 14 S.
Iron oxide nanoparticles are a promising platform for biomedical applications, both in terms of diagnostics and therapeutics. In addition, arginine-rich polypeptides are known to penetrate across cell membranes. Here, we thus introduce a system based on magnetite nanoparticles and the polypeptide poly-l-arginine (polyR-Fe3O4). We show that the hybrid nanoparticles exhibit a low cytotoxicity that is comparable to Resovist®, a commercially available drug. PolyR-Fe3O4 particles perform very well in diagnostic applications, such as magnetic particle imaging (1.7 and 1.35 higher signal respectively for the 3rd and 11th harmonic when compared to Resovist®), or as contrast agents for magnetic resonance imaging (R2/R1 ratio of 17 as compared to 11 at 0.94 T for Resovist®). Moreover, these novel particles can also be used for therapeutic purposes such as hyperthermia, achieving a specific heating power ratio of 208 W/g as compared to 83 W/g for Feridex®, another commercially available product. Therefore, we envision such materials to play a role in the future theranostic applications, where the arginine ability to deliver cargo into the cell can be coupled to the magnetite imaging properties and cancer fighting activity.
https://doi.org/10.3390/nano10102014
A KPI-based soft sensor development approach incorporating infrequent, variable time delayed measurements. - In: IEEE transactions on control systems technology, ISSN 1558-0865, Bd. 28 (2020), 6, S. 2523-2531
The overall performance of complex industrial systems using control and optimization strategies is often hampered by the lack of available measurements of key quality variables. The development of a soft sensor is a solution that allows for the necessary process information to be made available. Due to the nonlinear characteristics of industrial processes, a new soft sensor development approach that incorporates infrequent, variable time delayed measurements is proposed. Based on the fast-sampled measurement and the nonlinear, first principles model, the frequent and delay-free key performance indicator (KPI) estimation is realized using the square-root unscented Kalman filter (SR-UKF). Then, a modified Kalman Filter (MKF) algorithm is proposed to deal with those infrequent, but accurate measurements, whose values are variably delayed in time. These two types of estimates are fused and optimized to give an optimal, reliable KPI estimate based on the distributed state fusion UKF filter algorithm. The performance and effectiveness of the proposed approach are demonstrated by an experimental application for alumina concentration monitoring in the aluminum electrolysis industry.
https://doi.org/10.1109/TCST.2019.2929478
Metal-insulator transition in crystalline V2O3 thin films probed at atomic-scale using emission Mössbauer spectroscopy. - In: Thin solid films, ISSN 1879-2731, Bd. 714 (2020), 138389
Im Titel sind "2" und "3" tiefgestellt
Microscopic understanding the metal-to-insulator transition (MIT) in strongly correlated materials is critical to the design and control of modern "beyond silicon" Mott nanodevices. In this work, the local MIT behaviors in single crystalline V2O3 thin films were probed on an atomic scale by online 57Fe emission Mössbauer spectroscopy (eMS) following dilute (<10^-3 at.%) implantation of 57Mn+ (T1/2 = 90 s). Both the epitaxial and the textured V2O3 thin films grown by direct current magnetron sputtering were studied. Three structural components were resolved and identified in the eMS spectra with parameters characteristic of Fe in the 2+ valence state, which are attributable to Fe in either lattice damage or structural defects and Fe in the intrinsic crystal structure of V2O3, respectively. The results prove that the oxygen vacancies are common in the V2O3 thin films. With co-existence of both the non-stoichiometry and epitaxial strain in the thin films, the epitaxial strain plays a dominant role in controlling the global MIT properties of the film. The atomic scale structural transition captured by the eMS affirms the early-stage dynamics of the MIT of V2O3 thin film reported previously. These results approve the feasibility to tune the electronic transport of the V2O3 thin films for the next-generation Mott nanodevices by the epitaxial strain via the sample growth parameters.
https://doi.org/10.1016/j.tsf.2020.138389
C60 fullerene governs doxorubicin effect on metabolic profile of rat microglial cells in vitro. - In: Molecular pharmaceutics, ISSN 1543-8392, Bd. 17 (2020), 9, S. 3622-3632
Im Titel ist "60" tiefgestellt
Background: C60 fullerenes and their derivatives are actively investigated for the use in neuroscience. Applications of these nanoscale materials require the examination of their interaction with different neural cells, especially with microglia, because these cells, like other tissue resident phagocytes, are the earliest and most sensitive responders to nanoparticles. The aim of this study was to investigate the effect of C60 fullerene and its nanocomplex with doxorubicin (Dox) on the metabolic profile of brain-resident phagocytes - microglia - in vitro. Methods: Resting microglial cells from adult male Wistar rats were used in experiments. Potential C60 fullerene targets in microglial cells were studied by computer simulation. Microglia oxidative metabolism and phagocytic activity were examined by flow cytometry. Griess reaction and arginase activity colorimetric assay were used to explore arginine metabolism. Results: C60 fullerene when used alone did not influence microglia oxidative metabolism and phagocytic activity but shifted arginine metabolism toward the decrease of NO generation. Complexation of C60 fullerene with Dox (C60-Dox) potentiated the ability of the latter to stimulate NO generation. Conclusion: The capability of C60 fullerenes used alone to cause anti-inflammatory shift of microglia arginine metabolism makes them a promising agent for the correction of neuroinflammatory processes involved in neurodegeneration. The potentiating action of C60 fullerene on the immunomodulatory effect of Dox allows us to consider the C60 molecule as an attractive vehicle for this antitumor agent.
https://doi.org/10.1021/acs.molpharmaceut.0c00691
Evaluation of the biocompatibility of water-soluble pristine 60 fullerenes in rabbit. - In: BioNanoScience, ISSN 2191-1649, Bd. 10 (2020), 3, S. 721-730
Im Titel ist "60" tiefgestellt
C60 fullerenes have proved their therapeutic effects and efficacy by the results of countless experiments. For further usage of these nanoparticles, the systematic toxicological investigations are required. Blood compatibility should be studied for C60 fullerenes due to the potential blood contact. Currently, available data is not systematic and has not provided insights into possible side effects of C60 fullerenes on blood components. In this study, water-soluble pristine C60 fullerenes were tested in vitro to assess their biocompatibility in rabbit. The blood compatibility has been evaluated looking at the impact of C60 fullerenes on erythrocyte integrity, platelet aggregation, and some blood factors involved in coagulation. Our results revealed that C60 fullerenes cannot elicit hemolysis at studied concentrations and did not show any effect on coagulation process. C60 fullerenes in concentration-dependent manner increased ADP-dependent platelet aggregation and changed the key kinetic parameters of these processes. C60 fullerenes inhibited thrombin amidolytic activity but did not affect the activities of other studied coagulation factors. The prothrombotic property of C60 fullerenes could be the potential risk factor that leads to enhancement of vascular thrombosis. The ability of fullerene to inhibit thrombin activity is important for the pharmacological use of these carbon nanoparticles as anticoagulant agents.
https://doi.org/10.1007/s12668-020-00762-w
Synthesis and characterization of citrate-stabilized gold-coated superparamagnetic iron oxide nanoparticles for biomedical applications. - In: Molecules, ISSN 1420-3049, Bd. 25 (2020), 19, 4425, insges. 23 S.
Surface-functionalized gold-coated superparamagnetic iron oxide nanoparticles (Au-SPIONs) may be a useful tool in various biomedical applications. To obtain Au-SPIONs, gold salt was precipitated onto citrate-stabilized SPIONs (Cit-SPIONs) using a simple, aqueous one-pot technique inspired by the Turkevich method of gold nanoparticle synthesis. By the further stabilization of the Au-SPION surface with additional citrate (Cit-Au-SPIONs), controllable and reproducible Z-averages enhanced long-term dispersion stability and moderate dispersion pH values were achieved. The citrate concentration of the reaction solution and the gold/iron ratio was found to have a major influence on the particle characteristics. While the gold-coating reduced the saturation magnetization to 40.7% in comparison to pure Cit-SPIONs, the superparamagnetic behavior of Cit-Au-SPIONs was maintained. The formation of nanosized gold on the SPION surface was confirmed by X-ray diffraction measurements. Cit-Au-SPION concentrations of up to 100 [my]g Fe/mL for 48 h had no cytotoxic effect on Jurkat cells. At a particle concentration of 100 [my]g Fe/mL, Jurkat cells were found to take up Cit-Au-SPIONs after 24 h of incubation. A significantly higher attachment of thiol-containing L-cysteine to the particle surface was observed for Cit-Au-SPIONs (53%) in comparison to pure Cit-SPIONs (7%).
https://doi.org/10.3390/molecules25194425
Rapid and controllable synthesis of nanocrystallized nickel-cobalt boride electrode materials via a mircoimpinging stream reaction for high performance supercapacitors. - In: Small, ISSN 1613-6829, Bd. 16 (2020), 39, 2003342, insges. 13 S.
Nickel-cobalt borides (denoted as NCBs) have been considered as a promising candidate for aqueous supercapacitors due to their high capacitive performances. However, most reported NCBs are amorphous that results in slow electron transfer and even structure collapse during cycling. In this work, a nanocrystallized NCBs-based supercapacitor is successfully designed via a facile and practical microimpinging stream reactor (MISR) technique, composed of a nanocrystallized NCB core to facilitate the charge transfer, and a tightly contacted Ni-Co borates/metaborates (NCBi) shell which is helpful for OH^- adsorption. These merits endow NCBNCBi a large specific capacity of 966 C g^-1 (capacitance of 2415 F g^-1) at 1 A g^-1 and good rate capability (633.2 C g^-1 at 30 A g^-1), as well as a very high energy density of 74.3 Wh kg^-1 in an asymmetric supercapacitor device. More interestingly, it is found that a gradual in situ conversion of core NCBs to nanocrystallized Ni-Co (oxy)-hydroxides inwardly takes place during the cycles, which continuously offers large specific capacity due to more electron transfer in the redox reaction processes. Meanwhile, the electron deficient state of boron in metal-borates shells can make it easier to accept electrons and thus promote ionic conduction.
https://doi.org/10.1002/smll.202003342
Investigation of epitaxial graphene via Raman spectroscopy: origins of phonon mode asymmetries and line width deviations. - In: Carbon, ISSN 1873-3891, Bd. 170 (2020), S. 666-676
In this work a comprehensive study is presented for the analysis of epitaxial graphene layers using Raman spectroscopy. A wide range of graphene types is covered, from defective/polycrystalline single layer graphene to multilayer graphene with low defect density. On this basis the influence of strain type, Fermi level and number of layers on the Raman spectrum of graphene is investigated. A detailed view on the 2D/G dispersion and the respective slopes of uniaxially and biaxially strained graphene is given and its implications on the asymmetry of the G peak analyzed. A linear dependency of the phonon mode asymmetry on uniaxial strain is presented in addition to the known Fermi level dependence. Additional impacts on the asymmetry are found to be arising from the defect density and transfer doping of adsorbates. The discovered transfer doping mechanism is contrary to pure phonon excitation through excitons and exhibits increasing asymmetry with increasing Fermi level. A new characteristic correlation between the 2D mode line width and the inverse I(D)/I(G) ratio is introduced that allows the determination of the strain type and layer number and explains the difference between Raman line widths of monolayer graphene on different substrates.
https://doi.org/10.1016/j.carbon.2020.07.016
A close step towards industrialized application of solar water splitting. - In: Journal of semiconductors, ISSN 2058-6140, Bd. 41 (2020), 9, 090401, S. 1-3
https://doi.org/10.1088/1674-4926/41/9/090401
Collagen-iron oxide nanoparticle based ferrogel: large reversible magnetostrains with potential for bioactuation. - In: Multifunctional materials, ISSN 2399-7532, Volume 3 (2020), number 3, 035001, Seite 1-10
Smart materials such as stimuli responsive polymeric hydrogels offer unique possibilities for tissue engineering and regenerative medicine. As, however, most synthetic polymer systems and their degradation products lack complete biocompatibility and biodegradability, this study aims to synthesize a highly magnetic responsive hydrogel, based on the abundant natural biopolymer collagen. As the main component of vertebratal extracellular matrix, it reveals excellent biocompatibility. In combination with incorporated magnetic iron oxide nanoparticles, a novel smart nano-bio-ferrogel can be designed. While retaining its basic biophysical properties and interaction with living cells, this collagen-nanoparticle hydrogel can be compressed to 38% of its original size and recovers to 95% in suitable magnetic fields. Besides the phenomenology of this scenario, the underlying physical scenarios are also discussed within the framework of network models. The observed reversible peak strains as large as 150% open up possibilities for the fields of biomedical actuation, soft robotics and beyond.
https://doi.org/10.1088/2399-7532/abaa2d